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Abstract

Background: Many families find regular checking of children’s heads for head louse infestation too onerous and would prefer to be able to prevent infestation by use of a topical application that deters lice from infesting the head. Identification in the laboratory of a repellent activity for piperonal provided the basis for developing a spray product to repel lice.

Methods: A proof of principle field study in Dhaka, Bangladesh, compared the effect of using 2% piperonal spray with that of a placebo in 105 children and adults from three communities with infestation levels close to 100%. All participants were treated for infestation and subsequent incidence of reinfestation monitored daily by investigators. A second randomised, controlled, double blind, study in North London, UK, evaluated the effect of the product in normal use. One hundred and sixty-three children from schools with a high level (20-25%) of infestation were treated and confirmed louse free and randomly divided between 2% piperonal, a placebo spray, and a control group for up to 22 weeks. Parents applied the spray and monitored for infestation. Regular investigator visits confirmed the parental monitoring and replenished supplies of spray.

Results: In Dhaka, over 18 days there were only 4 infestations in the piperonal group and 8 in the placebo group. This difference was not significant (p = 0.312). In North London, there were 41 cases of infestation over the course of the study. Analysis of time to first infestation showed a non-significant (p = 0.4368) trend in favour of piperonal.

Conclusion: Routine use of 2% piperonal spray in communities with a high prevalence of head louse infestation may provide some protection from infestation. However, the difference between use of the product and no active intervention was sufficiently small that regular checking for presence of lice is likely to be a more practical and cost effective approach to prevention of infestation.

Supplemental Information

Protocol for the London study

CONSORT checklist

Additional Information

Competing Interests

None of the authors have, or are likely to have, any competing interests arising from submission and publication of this manuscript.

Judith Kaufman is an employee of Royalheath Charitable Trust Limited. Other authors are, or were (Christine Brown is now retired), employees of the Medical Entomology Centre and received only salary emoluments whilst involved in performing this work.

Author Contributions

Ian F Burgess conceived and designed the experiments, performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables, reviewed drafts of the paper.

Christine M Brown conceived and designed the experiments, performed the experiments, reviewed drafts of the paper.

Nazma A Burgess conceived and designed the experiments, performed the experiments, reviewed drafts of the paper, community liaison Bangladesh, translation services.

Judith Kaufman conceived and designed the experiments, performed the experiments, reviewed drafts of the paper, community liaison London, pharmacy services.

Human Ethics

The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):

Funding

The initial laboratory investigations and field studies were supported financially by Charwell Pharmaceuticals Ltd, Alton, UK, as part of a new product development programme prior to their acquisition by Pfizer Inc., and inclusion in Unicliffe Limited. Employees of Charwell Pharmaceuticals Ltd filed patents based on the work in support of a commercial product launch, but that intellectual property has now lapsed. The company did contribute ideas towards the design of the studies and conducted their own analyses of the results, which were not disclosed to the investigators. David Merrington contracted the work and William (Bill) Oliver and Richard Irwin provided technical and logistical support and study supplies. Monitoring of documentation from both field studies was performed by an appointee of Pfizer Inc. on behalf of Charwell Pharmaceuticals Ltd. Only as far as is stated in the Funding Statement

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